173 research outputs found

    Clinical Status of Adolescents with Perinatal HIV at Transfer to Adult Care in the UK/Ireland

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    BACKGROUND: Increasing numbers of children infected perinatally with human immunodeficiency virus (HIV) are surviving to adolescence and transitioning to adult care, yet there are scarce data on their clinical status at transfer. METHODS: We analyzed prospective cohort data from the UK/Ireland national Collaborative HIV Pediatric Study (CHIPS). Clinical status at last pediatric clinic visit prior to transfer was described. Factors associated with higher CD4 cell count and viral load (VL) suppression<400 c/mL among patients on antiretroviral therapy (ART) at transfer were assessed using linear and logistic regression, respectively. Data were matched with the UK HIV Drug Resistance Database (UKHIVDRB) to assess cumulative resistance profiles at transfer. RESULTS: Of 1,907 children followed in CHIPS from 1996 to November 2014, 644 (34%) transferred to adult care: 53% were female, 62% born outside the UK/Ireland, 75% black African. At last pediatric follow-up, median age was 17.4 years [interquartile range 16.5,18.1], 27% had previous AIDS diagnosis, CD4 was 444 cells/mm3 [280, 643], 76% were on ART, 13% off-ART, and 11% ART-naive. Among patients on ART, 74% had VL<400 c/mL. In multivariable analysis, higher CD4 at transfer was associated with younger age, higher CD4 at ART initiation and lower VL at transfer (P ≤ .001). Predictors of viral suppression include no AIDS diagnosis and later year of transfer (P ≤ .05). Of 291 patients with resistance data, 82% had resistance to ≥1 drug class, 56% to ≥2 classes and 12% had triple-class resistance. CONCLUSION: Three-quarters of adolescents were on stable ART at transfer, of whom 74% were virologically suppressed. The prevalence of triple-class resistance was relatively low at 12%

    UK national clinical audit: Management of pregnancies in women with HIV

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    BACKGROUND: The potential for HIV transmission between a pregnant woman and her unborn child was first recognized in 1982. Since then a complex package of measures to reduce risk has been developed. This project aims to review UK management of HIV in pregnancy as part of the British HIV Association (BHIVA) audit programme. METHODS: The National Study of HIV in Pregnancy and Childhood (NSHPC), a population-based surveillance study, provided data for pregnancies with an expected delivery date from 1/1/13 - 30/6/14. Services also completed a survey on local management policies. Data were audited against the 2012 BHIVA pregnancy guidelines. RESULTS: During the audit period 1483 pregnancies were reported and 112 services completed the survey. Use of dedicated multidisciplinary teams was reported by 99% although 26% included neither a specialist midwife nor nurse. 17% of services reported delays >1 week for HIV specialist review of women diagnosed antenatally. Problematic urgent HIV testing had been experienced by 9% of services although in a further 49% the need for urgent testing had not arisen. Delays of >2 h in obtaining urgent results were common. Antiretroviral therapy (ART) was started during pregnancy in 37% women with >94% regimens in accordance with guidelines. Late ART initiation was common, particularly in those with a low CD4 count or high viral load. Eleven percent of services reported local policy contrary to guidelines regarding delivery mode for women with a VL <50 copies/mL at ≥36 weeks. According to NSHPC reports 27% of women virologically eligible for vaginal delivery planned to deliver by CS. CONCLUSIONS: Pregnant women in the UK are managed largely in accordance with BHIVA guidelines. Improvements are needed to ensure timely referral and ART initiation to ensure the best possible outcomes

    Young people in the United Kingdom and Ireland with perinatally acquired HIV: The pediatric legacy for adult services

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    Children with perinatally acquired HIV-1 infection are surviving into adolescence and increasingly transitioning toward adult services. Planning appropriate services in adult life requires an understanding of their progress through pediatric care. We describe the demographic features, disease progression, antiretroviral therapy (ART), and resistance in young people aged 10 years or more living in the United Kingdom and Ireland reported to the National Study of HIV in Pregnancy and Childhood (NSHPC) with prospective annual follow-up in the Collaborative HIV Paediatric Study (CHIPS) between 1996 and September 2007. Six hundred fifty-four perinatally infected young people were identified; 76% black African, 57% born abroad. Median age at presentation and duration of follow-up was 1 and 11 years, respectively, if born in the United Kingdom/Ireland, and 8 and 5 years if born elsewhere. One hundred sixty-nine (26%) ever had an AIDS-defining illness. Ten died during adolescence. At last follow-up, 64% were on ART, 18% off treatment having previously received ART and 18% were ART naive. Of 518 who had received highly active antiretroviral therapy (HAART), 47% were triple class experienced. At last follow-up 77 (12%) had CD4 counts less than 200 per microliter; of those on HAART, 78% had HIV-1 RNA <= 400 copies per milliliter, median CD4 count 554 (interquartile range [IQR] 324-802). Among 166 with resistance assays on HAART, 52% and 12% had dual- and triple-class HIV-1-associated resistance mutations, respectively. One hundred three (16%) young people had transferred to adult services. Young adults with perinatally acquired HIV-1 infection require coordinated multidisciplinary transitional care services and careful long-term follow-up in adult life

    CD4 cell count and the risk of AIDS or death in HIV-Infected adults on combination antiretroviral therapy with a suppressed viral load: a longitudinal cohort study from COHERE.

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    BACKGROUND: Most adults infected with HIV achieve viral suppression within a year of starting combination antiretroviral therapy (cART). It is important to understand the risk of AIDS events or death for patients with a suppressed viral load. METHODS AND FINDINGS: Using data from the Collaboration of Observational HIV Epidemiological Research Europe (2010 merger), we assessed the risk of a new AIDS-defining event or death in successfully treated patients. We accumulated episodes of viral suppression for each patient while on cART, each episode beginning with the second of two consecutive plasma viral load measurements 500 copies/µl, the first of two consecutive measurements between 50-500 copies/µl, cART interruption or administrative censoring. We used stratified multivariate Cox models to estimate the association between time updated CD4 cell count and a new AIDS event or death or death alone. 75,336 patients contributed 104,265 suppression episodes and were suppressed while on cART for a median 2.7 years. The mortality rate was 4.8 per 1,000 years of viral suppression. A higher CD4 cell count was always associated with a reduced risk of a new AIDS event or death; with a hazard ratio per 100 cells/µl (95% CI) of: 0.35 (0.30-0.40) for counts <200 cells/µl, 0.81 (0.71-0.92) for counts 200 to <350 cells/µl, 0.74 (0.66-0.83) for counts 350 to <500 cells/µl, and 0.96 (0.92-0.99) for counts ≥500 cells/µl. A higher CD4 cell count became even more beneficial over time for patients with CD4 cell counts <200 cells/µl. CONCLUSIONS: Despite the low mortality rate, the risk of a new AIDS event or death follows a CD4 cell count gradient in patients with viral suppression. A higher CD4 cell count was associated with the greatest benefit for patients with a CD4 cell count <200 cells/µl but still some slight benefit for those with a CD4 cell count ≥500 cells/µl

    Shattered pellet injection experiments at JET in support of the ITER disruption mitigation system design

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    A series of experiments have been executed at JET to assess the efficacy of the newly installed shattered pellet injection (SPI) system in mitigating the effects of disruptions. Issues, important for the ITER disruption mitigation system, such as thermal load mitigation, avoidance of runaway electron (RE) formation, radiation asymmetries during thermal quench mitigation, electromagnetic load control and RE energy dissipation have been addressed over a large parameter range. The efficiency of the mitigation has been examined for the various SPI injection strategies. The paper summarises the results from these JET SPI experiments and discusses their implications for the ITER disruption mitigation scheme

    New H-mode regimes with small ELMs and high thermal confinement in the Joint European Torus

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    New H-mode regimes with high confinement, low core impurity accumulation, and small edge-localized mode perturbations have been obtained in magnetically confined plasmas at the Joint European Torus tokamak. Such regimes are achieved by means of optimized particle fueling conditions at high input power, current, and magnetic field, which lead to a self-organized state with a strong increase in rotation and ion temperature and a decrease in the edge density. An interplay between core and edge plasma regions leads to reduced turbulence levels and outward impurity convection. These results pave the way to an attractive alternative to the standard plasmas considered for fusion energy generation in a tokamak with a metallic wall environment such as the ones expected in ITER.&amp; nbsp;Published under an exclusive license by AIP Publishing

    Predictive JET current ramp-up modelling using QuaLiKiz-neural-network

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    This work applies the coupled JINTRAC and QuaLiKiz-neural-network (QLKNN) model on the ohmic current ramp-up phase of a JET D discharge. The chosen scenario exhibits a hollow T-e profile attributed to core impurity accumulation, which is observed to worsen with the increasing fuel ion mass from D to T. A dynamic D simulation was validated, evolving j, n(e), T-e, T-i, n(Be), n(Ni), and n(W) for 7.25 s along with self-consistent equilibrium calculations, and was consequently extended to simulate a pure T plasma in a predict-first exercise. The light impurity (Be) accounted for Z(eff) while the heavy impurities (Ni, W) accounted for Prad. This study reveals the role of transport on the Te hollowing, which originates from the isotope effect on the electron-ion energy exchange affecting T-i. This exercise successfully affirmed isotopic trends from previous H experiments and provided engineering targets used to recreate the D q-profile in T experiments, demonstrating the potential of neural network surrogates for fast routine analysis and discharge design. However, discrepancies were found between the impurity transport behaviour of QuaLiKiz and QLKNN, which lead to notable T-e hollowing differences. Further investigation into the turbulent component of heavy impurity transport is recommended

    Peripheral temperature gradient screening of high-Z impurities in optimised 'hybrid' scenario H-mode plasmas in JET-ILW

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    Screening of high-Z (W) impurities from the confined plasma by the temperature gradient at the plasma periphery of fusion-grade H-mode plasmas has been demonstrated in the JET-ILW (ITER-like wall) tokamak. Through careful optimisation of the hybrid-scenario, deuterium plasmas with sufficient heating power (greater than or similar to 32 MW), high enough ion temperature gradients at the H-mode pedestal top can be achieved for the collisional, neo-classical convection of the W impurities to be directed outwards, expelling them from the confined plasma. Measurements of the W impurity fluxes between and during edge-localised modes (ELMs) based on fast bolometry measurements show that in such plasmas there is a net efflux (loss) between ELMs but that ELMs often allow some W back into the confined plasma. Provided steady, high-power heating is maintained, this mechanism allows such plasmas to sustain high performance, with an average D-D neutron rate of similar to 3.2 x 10(16) s(-1) over a period of similar to 3 s, after an initial overshoot (equivalent to a D-T fusion power of similar to 9.4 MW), without an uncontrolled rise in W impurity radiation, giving added confidence that impurity screening by the pedestal may also occur in ITER, as has previously been predicted (Dux et al 2017 Nucl. Mater. Energy 12 28-35)
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